What are the side effects?

You may experience bowel changes when taking Alli. These side effects can include:

  • Gas with an oily anal discharge
  • Loose stools or diarrhea
  • More-frequent bowel movements
  • Hard-to-control bowel movements

These bowel changes result from the undigested fat going through your digestive system. You can limit the side effects by eating a low-fat diet.

When shouldn't you take Alli?

Don't take Alli if you:

  • Are at a healthy weight
  • Are taking cyclosporine (Neoral, Sandimmune, others)
  • Have had an organ transplant
  • Have problems already absorbing food

Talk with your doctor about whether using Alli would be appropriate if you take blood-thinning medication or have diabetes or thyroid disease.

Orlistat decreases the absorption of certain fat-soluble vitamins — for example, vitamins A, D and E. If you're taking Alli, you need to take a daily vitamin supplement (at a time different from when you take Alli) to prevent potential nutrient deficiencies.

How long do I need to take Alli?

According to the manufacturer, most weight loss occurs within the first six months. Many people who take medications to lose weight regain the weight they lost when they stop taking the medication. Therefore, to keep the weight off, many people continue taking medications indefinitely along with eating a low-calorie diet and exercising regularly.

How does Alli fit into a healthy weight-loss plan?

As you consider Alli as a weight-loss aid, make sure that you make every effort to exercise, change your eating habits and adjust any other lifestyle factors that have contributed to your excess weight. Alli isn't the easy answer to weight loss and is meant only to supplement — not replace — a healthy diet and regular exercise.

Work with your doctor to evaluate the potential benefits and risks of Alli or any other weight-loss drugs. As a team, you and your doctor can create the most effective weight-loss plan for you.

Feb. 11, 2012 See more In-depth